An unexpected and persistent increase in global emissions of ozone-depleting CFC-11

摘要: The Montreal Protocol was designed to protect the stratospheric ozone layer by enabling reductions in abundance of ozone-depleting substances such as chlorofluorocarbons (CFCs) atmosphere1–3. reduction atmospheric concentration trichlorofluoromethane (CFC-11) has made second-largest contribution decline total chlorine since 1990s 1 . However, CFC-11 still contributes one-quarter all reaching stratosphere, and a timely recovery depends on sustained CFC-11 concentrations Here we show that rate concentrations observed at remote measurement sites constant from 2002 2012, then slowed about 50 per cent after 2012. slowdown concurrent with increase mean difference between Northern Southern Hemispheres, also emergence strong correlations Mauna Loa Observatory other chemicals associated anthropogenic emissions. A simple model analysis our findings suggests an emissions 13 ± 5 gigagrams year (25 ± 13 cent) despite reported production being close zero 4 2006. Our three-dimensional simulations confirm emissions, but indicate this may have been much smaller result changes processes or dynamics. emission appears unrelated past production; unreported new production, which is inconsistent agreement phase out global CFC 2010.